The present disclosure generally provides apparatuses for evaluating the integrity of a container seal. More particularly, the present disclosure provides apparatuses for evaluating the seal integrity of liquid-filled containers of varying sizes, and methods for evaluating such seals.
Containers with resealable closures are used throughout the food and beverage industry. The closures are designed to prevent product leakage and yet they must also provide the user with easy open access to the contents of the container. Resealable closures are appropriate when the container contents are beverages or food products because these closures enable consumers to dispense a desired portion of the beverage or food product and then reseal the remainder of the product for later consumption. One problem with this type of sealed container is leakage, which is more common, for example, with plastic containers.
For plastic containers, the leaks are primarily attributable to processing conditions such as heat exposure, finish abrasions, fill temperature, head space, pull-up range, and inversion. When the seal on a plastic container fails, the liquid or food contents of the container can become contaminated and the container is not suitable for sale to the public. As a result, the container and the contents must be discarded with the manufacturer experiencing a reduction in product output.
U.S. Pat. No. 5,535,618 to Konieczka (“the '618 patent”) discloses a destructive method for testing for leaks in sealed containers. The method of that invention includes measuring for electrical conductivity between contents of a sealed container and an electrolyte solution in which the container is partially immersed. The method disclosed in the patent detects a container seal leak if there is electric current flowing from an electrode in a solution to a second electrode positioned within the container contents. Conversely, if no electric current flow is detected, then the container seal is not leaking.
A device currently used in accordance with the teachings of the '618 patent for testing container seals requires the operator to perform two distinct, time consuming steps. In a first jig, the operator must pierce a surface of the container with a drill bit mounted in a drill press. Next, the operator must transport the container to a testing device and properly secure the container before beginning the testing procedure. Since the liquid contents of the container can be spilled while transporting the pierced container, the device has an inherent level of imprecision which can affect the accuracy of test results and the verification of earlier test results. In addition, the components comprising the testing devices are numerous and are not integrated into a single apparatus. As a result, the testing device is inefficiently packaged and consumes a disproportionate amount of workspace. Also, because the prior device is immobile, the operator is precluded from repositioning the testing device or temporarily moving the testing device closer to or away from the container production line.
The prior conventional test apparatus of the '618 patent employs a manually moved member to secure and deform the container during the test process. In the conventional apparatus, developing the necessary force to deform or squeeze the container requires muscular exertion by a human operator. Accordingly, the manually moved member is subject to variation based upon the individuality of the operation and the operator, which further reduces the precision of the testing results. Also, during the course of a typical day, the operator can experience some fatigue when repeatedly applying the necessary muscular exertion to the manually moved member. Further, the manually moved member (i.e., a hand crank) requites a significant time element to operate, which further reduces the sampling rate of the device. Moreover, because an external pressure source is used by the apparatus of the '618 patent, and because the rigidity of plastic containers can vary, the amount of pressure inside the container cannot be quantified at the point of seal rupture.